Don said:
"As to whether segments of DNA "have no use," it's far too early in the process of DNA analysis to jump to such conclusion, partly because it's strictly impossible to prove that a thing has no use. "

If you look at the gene for the enzyme of asorbic acid in a lower life-form, you can see it has a definite use. When you see a retarded copy in the human genome, the implication is obvious. First, the gene has a function in lower life-forms. Second, the function doesn't work as intended for us (since it is retarded, truncated, or otherwise destroyed), so we need an external source of Vitamin C. People can refuse to see the obvious implications if they want, but I don't think they should be tolerated because it is illogical and just plain ignorant to ignore the plain consequences.

Asorbic acid is supposedly one of 1,000's of pseudogenes in the human genome. That's why the DNA evidence is overwhelming for evolution.

It is like seeing footprints leading to the cookie jar. If the footprint matches my kid's foot, I don't care what excuse they have- they did it. Some parents will refuse to see the evidence because they want to believe junior is a little angel. People can be very creative in brushing-off the obvious implications of the data.

"There is lots of DNA that is carried-over from previous organisms and they have no use in our genome. In this way they are "biological fossils." I think the DNA is much more better evidence for evolution, and fossils aren't even needed."

A key point in what I wrote is that YOU DON'T KNOW from the DNA itself that THERE ARE ANY "previous organisms." Any knowledge of previous organisms must come from some source other than DNA. What you (and others who assert such things) are doing is asserting evolution before you look at any DNA and then saying that DNA implies what you assert. This is a kind of circular reasoning, except that we really do know from other sources that previous organisms existed. Without those other sources (e.g., fossils) we could not know that previous organisms existed. (How else is it possible to say such a simple thing to make it any clearer?)

We all believe a "designer" exists; from the DNA itself you cannot exclude the possibility that "God just made it all as we find it." As to whether segments of DNA "have no use," it's far too early in the process of DNA analysis to jump to such conclusion, partly because it's strictly impossible to prove that a thing has no use.

Referring to your ABCD below, note that your model at the outset assumes--not proves--evolution. In general you absolutely do not know from the genes alone that anything descended from anything else. Once you ASSUME common descent, then your arguments can have merit. But it's plausible to one who believes in God and knows nothing of Earth history that God simply used the same genes multiple times in different applications to get his desired results. All this God could have done simultaneously; no elapsed time necessary. Any "amazing coincidences," such as the fusion of chromosome #2, one could simply chalk up to God's inscrutability.

Even if you take Dawkins' position that no designer exists, it's still not possible from DNA alone to conclude evolution. The most you can legitimately conclude as a scientist is that there are intriguing relationships among various sets of DNA. You could even come up with an elaborate evolutionary scheme to account for those relationships, but it would still all be speculation, because you would have no hard evidence that "previous organisms" ever existed.

Without evidence that previous organisms existed, you cannot have evolution as science; and DNA by itself offers at best only handwaving speculations about the existence of previous organisms.

Unless you assume what you are trying to prove, you cannot get evolution from DNA alone.

What might be possible from DNA alone is a logical structure in support of evolution of such beauty that, like a mathematical proof, everybody comes to accept its validity. A logical structure, however, like a mathematical proof, is not science. Fortunately for evolution we have fossils, therefore we know previous organisms existed, and evolution becomes science.

"...The 'tree of life' can be constructed without even consulting fossils, and in fact will be different and more accurate than any tree deduced from fossils."

Not remotely possible, because we have DNA for only a tiny percentage of the inhabitants of the tree of life. How would DNA for these few tell you where the missing multitudes fit? In fact those missing multitudes are known exclusively from fossils. DNA can indicate a few important initial adjustments, but it's useless from there on.

Don said:
"If there's no evidence that later organisms differed from earlier ones, there's no reason to think evolution. By definition. Fossils in their historical context provide exactly this evidence that later organisms differed from earlier ones, so fossils offer reasons for proposing evolution. DNA evidence, on the other hand, is without its own historical context and therefore by itself provides no such motive: DNA cannot provide evidence that earlier organisms differed from later ones, because DNA exists only for existing organisms irrespective of where they fit on any time scale. DNA by itself does not contain a time scale and does not imply "earlier" or "later" for any organism. "

I disagree, and I think this is a very important point.

Specifically, your comment:
"DNA cannot provide evidence that earlier organisms differed from later ones, because DNA exists only for existing organisms irrespective of where they fit on any time scale. DNA by itself does not contain a time scale and does not imply "earlier" or "later" for any organism."

It is not true that DNA exists only for existing organisms. There is lots of DNA that is carried-over from previous organisms and they have no use in our genome. In this way they are "biological fossils." I think the DNA is much more better evidence for evolution, and fossils aren't even needed. As technology and knowledge of DNA increases, I think the 'tree of life' can be constructed without even consulting fossils, and in fact will be different and more accurate than any tree deduced from fossils.

The "DNA timeline" is also deduced like this:

Genome 'red' has gene A and B.
Genome 'blue' has gene B, C, D, and parts of A (non-functioning)
Genome 'yellow' has genes A, B, and C.

Therefore, organism 'yellow' is obviously descended from 'red' and is the ancestor of 'blue.'

All of this is determined without knowing anything at all about fossils or the age of the earth.

Bernie wrote: "...The genomic data...is demonstrating that evolution actually happened....It doesn't matter what fossils you have or how old the earth is to see the DNA changes between organisms.

If there's no evidence that later organisms differed from earlier ones, there's no reason to think evolution. By definition. Fossils in their historical context provide exactly this evidence that later organisms differed from earlier ones, so fossils offer reasons for proposing evolution. DNA evidence, on the other hand, is without its own historical context and therefore by itself provides no such motive: DNA cannot provide evidence that earlier organisms differed from later ones, because DNA exists only for existing organisms irrespective of where they fit on any time scale. DNA by itself does not contain a time scale and does not imply "earlier" or "later" for any organism.

Bottom line: Studies of DNA can show how genetic material of different organisms differs, but these findings by themselves say nothing about historical connections among organisms or even whether there are any such connections. Only when you inject historical context does it become worthwhile to look for historical connections; said historical context comes not from DNA but from Earth and fossil studies.

Bernie: "DNA al by itself can demonstrate that biological evolution happened (esp. the change from ape to human, with fused chromosome #2), beyond a reasonable doubt."

Fused chromosome #2 is not direct but circumstantial evidence, and it's not evidence for evolution at all unless you have external reasons for believing chimp & human had a common ancestor. Once you have reasons to believe chimp & human had a common ancestor, then the fused chromosome provides nice support. DNA evidence by itself offers no reason for believing chimp & human had a common ancestor. God could just have made it all that way; how unsearchable his ways....

IMO you're interpreting DNA info inside a preexisting evolutionary framework, so meanings you attach to DNA info actually derive not from DNA studies but from Earth history.

Don said:
"As I've pointed out N times already on this list, any "evidence for evolution" from DNA would be mere curiosity if (1) there were no fossil evidence of systematic changes in life forms with time and (2) there were no evidence that Earth is old."

I don't agree and/or don't understand. The DNA evidence can have nothing to do at all with fossils or an old earth. I'm saying the genomic data- comparing DNA across all plant/animal lifeforms, is demonstrating that evolution actually happened. There's lots of left-over junk in the DNA (pseudogenes for one) that show things were carried over and adapted. It doesn't matter what fossils you have or how old the earth is to see the DNA changes between organisms. Evolution (DNA evidence) perfectly explains why humans and chips have a retarded/unworking copy of the enzyme for ascorbic acid.

Yes- scientists can also get more out of DNA, such as estimating time when changes happened, but that is different than just seeing that evolution happened by comparing genomes, esp. that of chimp and human.

Don said:
"evidence from DNA is dependent on other kinds of evidence for its persuasiveness and hence is of secondary importance in establishing that macroevolution actually happened."

Bernie says, "The DNA evidence for evolution is overwhelming. In the same exact way, any court of law could say evolution happened beyond a reasonable doubt, because of the DNA evidence....I see no valid scientific way to explain away the DNA evidence...."

As I've pointed out N times already on this list, any "evidence for evolution" from DNA would be mere curiosity if (1) there were no fossil evidence of systematic changes in life forms with time and (2) there were no evidence that Earth is old.

(Obviously I enjoy pointing this out N+1 times!)

In other words, evidence from DNA is dependent on other kinds of evidence for its persuasiveness and hence is of secondary importance in establishing that macroevolution actually happened.

Don

To unsubscribe, send a message to majordomo@calvin.edu with
"unsubscribe asa" (no quotes) as the body of the message.
Received on Thu Jun 25 18:02:40 2009